Knockdown formwork for wall openings



April 22, 1969 A. HAIDER KNOCKDOWN FORMWORK FOR WALL OPENINGS Sheet of 2Filed Feb. 16. 1966 Alors Harder IN VE N TOR.

April 22, 1969 A. HAIDER 3,

KNOCKDOWN FORMWORK FOR WALL OPENINGS Filed Feb. 16. 1966 Sheet Z of 2Alois Hair/er INVENTOR.

Attorney United States Patent "ice 3,439,894 KN OCKDOWN FORMWORK FORWALL OPENINGS Alois Haider, 8261 Nonnreuth, Post Asten, Germany FiledFeb. 16, 1966, Ser. No. 527,960 Int. Cl. E0611 1/22 U.S. Cl. 249-39 7Claims ABSTRACT OF THE DISCLOSURE A formwork for openings in a wall inwhich corner components are joined by connected components having endfaces oblique to the periphery of the formwork. The components arejoined by lapping plates held in place by friction latches.

When houses are being constructed, openings are left in the walls forthe reception of windows. Suitable wooden boards have previously beenused as formwork for the wall openings. Such boards can be used only fora limited period of time because they can easily be damaged when theformwork is stripped (e.g., removed from the concrete structure).

It is already known to use a frame made from prefabricated parts, whichframe surrounds the wall opening in a part of the wall thickness andwhich remains in the wall, and to detachably secure formwork boards tothis frame, which surround the wall opening in the remainder of thethickness of the wall and which are removed when the resulting formworkhas been filled with wall material and the latter has set. The frame maycomprise angle members placed in the corners of the wall opening, andstraight bars disposed between said angle members. This formwork has thedisadvantage that the frame remains in the wall and cannot be reused.

Other formwork, particularly for lintels or headers for doors andwindows, is known which comprises two sheet metal troughs, which arelongitudinally adjustable relative to each other and can be fixed inposition. This formwork carries bars, which can be pushed out and arespaced from the extreme end of the trough and serve for supporting theentire formwork on the masonry which surrounds the opening. It iscomplicated to set such formwork in its correct position andsubsequently to remove it from the wall opening.

For concrete windows, formwork is known which has components that aremoved to their operative position by means of a complicated levermechanism and serve only as formwork for concrete windows.

It is an object of the invention to provide a knock-down formwork forwall openings, which formwork consists of parts which are detachabletoward the interior of the opening to strip the formwork. This isaccomplished in that the components of the formwork have in crosssection a step (across the plane of the assembly), which results in theformation of an abutment for the frame lining the opening; at least oneof the components of the formwork has two end faces which engage theremaining components of the formwork and which are oblique with respectto the longitudinal surface of the wall opening, and the peripheries ofthe formwork are parallel or larger on the inside of the wall than onthe outside thereof. This design facilitates the assembling of theformwork and its removal after use, It is preferable to use selectivelyinsertable connecting bars, which enable an adjustment of the size ofthe formwork to the desired size of the wall opening.

The invention relates also to details of the formwork.

Compared to the known types of formwork, the formwork according to theinvention has the advantage that it 3,439,894 Patented Apr. 22, 1969 canbe reused practically indefinitely, can be designed for a very Widerange of profiles, can easily be stripped, and can easily be adjusted todifferent sizes of windows by the aid of connecting bars.

An embodiment of the formwork according to the invention for a windowopening will now be explained by way of example with reference to theaccompanying drawing, in which FIG. 1 is a perspective view showing aformwork with connecting bars and FIG. 2 is a vertical sectional viewtaken through the formwork in position for use.

The formwork shown in FIG. 1 comprises four corner pieces 1, 2, 3 and 4and four connecting bars 5, 6, 7 and 8. Of the latter, three bars 5, 6,7 are shown in inserted position whereas the fourth bar 8 is shown in adetached position (FIG. 1).

The connecting bars 5, 6 and 7 abut the corner pieces of the formwork.At 20, where the connecting bar 8 is to be inserted, one of the twocomponents to be joined is provided with sheet metal lap elements 10 andthe other with retaining pins 9, which are received by bores 16 of theselap elements 10 for an additional initial fixation of the formworkcomponents 3, 4 and 8.

The corner piece 3 carries near its end adjacent to the connecting bar 8a pin 31, on which a friction latch 11 is pivotally mounted. Theconnecting bar 8 is provided near its end adjacent to the corner piece 3with a keeper lug 12, which is spaced from the adjacent face of theconnecting bar 8. In the assembled formwork, the latch 31 isfrictionally held between the lug 12 and the adjacent face of the bar 8.

The joints between components 4, 5, 1, 6, 2, 7 and 3 are at an angle ofapproximately 45 to the periphery so that the corner piece 1 can easilybe removed inwardly during stripping. The joints between parts 4, 8 and3 are at right angles to the periphery.

It will be understood that the joints between components 4, 5, 1, 6, 2,7 and 3 need not extend at an angle of exactly 45 It is essential,however, that one of the components of the formwork, e.g., the cornerpiece 1 in FIG. 1, has opposite end faces 32 and 33, which engageadjacent components of said formwork; one of said opposite end facesextends from the outside periphery of the formwork to the insideperiphery of the formwork in a direction which is at an oblique angle tothe direction of the outside periphery of the formwork adjacent to saidone end face; and the other of said opposite end faces extends from theoutside periphery of said formwork to the inside periphery of saidformwork in a direction which is nonconvergent, i.e., parallel ordivergent, to said direction of the first-mentioned one of said endfaces. Besides, each component of the formwork has inwardly andoutwardly facing edge faces 34 and 35 and the length of the outwardlyfacing edge face 35 of each component is, e.g., in the case of theconnecting bars 5, 6, 7, 8, as large as or, e.g., in the case of thecorner pieces 1, 2, 3, 4 larger than the length of the inwardly facingedge face 34 of the same component.

Stitfening angles 13 are provided in the corners and have a nail hole 14so that nails 21 inserted through these nail holes can be driven tosecure the formwork to the formwork wall 15 adjoining the outsidesurface 23 of the wall 22. The inside surface of the wall 22 has thereference numeral 24.

As is apparent from the drawings, the top 17 and the two sides 18 of theformwork extend in their transverse direction at right angles to theplane of the wall whereas the bottom 19 extends in its transversedimension at an oblique angle to the plane of the wall to facilitatestripping. To strip the formwork, the friction latches 11 are turnedabout their pins 31 so that the connecting bars 8 can easily be removed.The top 17 and the two sides 18 of the formwork have a step 25 betweenan outer portion 26 and an inner portion 27. The bottom 19 is alsoprovided with such a step 25 between outer portion 26 and an innerportion 29. The step 25 results in the formation of an abutment for thewindow frame 30, which is indicated in broken lines in FIG. 2, andprevents an angular misalignment of this frame relative to the wall 22.

The formwork is preferably made from a material which has asmalladhesion to concrete, e.g., of sheet metal or plastics material.

What is claimed is:

1. A knockdown formwork for wall openings, comprising a plurality ofdetachably connected components, at least one of said components havingopposite end faces which engage adjacent components of said form- Work,one of said opposite end faces extending from the outside periphery ofsaid formwork to the inside periphery of said formwork in a directionwhich is at an oblique angle to the direction of the outside peripheryof said formwork adjacent to said one end face, the other of saidopposite end faces extending from the outside periphery of said formworkto the inside periphery of said formwork in a direction which isnonconvergent to said direction of said one end face, each of saidcomponents of said formwork having inwardly and outwardly facing edgefaces, the length of the outwardly facing edge face of each componentbeing at least as large as the length of the inwardly facing edge faceof the same component, said components being formed on their outsideperipheral surface with a step which faces generally in the samedirection as said outwardly facing edge face, said components comprisingcorner pieces and connecting pieces between said corner pieces.

2. A formwork as defined in claim 1 wherein both said end faces of saidone component are parallel.

3. A formwork as defined in claim 1 wherein said directions of said twoend faces are divergent.

4. A formwork as defined in claim 1 wherein said direction of said otherend face is at an oblique angle to the direction of the outsideperiphery of said formwork adjacent to said other end face.

5. A formwork as defined in claim 1 wherein at least one of saidcomponents is provided at one end with a lap portion formed with a boreand another of said components is disposed adjacent to said lap portionand provided with a retaining pin inserted in said bore.

6. A formwork as defined in claim 1 wherein one of two adjacentcomponents is provided near its end with a keeper lug spaced from theadjacent face of said one component and the other of said two adjacentcomponents is provided with a pivoted friction latch frictionally heldbetween said lug and said adjacent face of said one component.

7. A knockdown formwork for wall openings, comprising a plurality ofdetachably connected components, at least one of said components havingopposite end faces which engage adjacent components of said formwork,one of said opposite end faces extending from the outside periphery ofsaid formwork to the inside periphery of said formwork in a directionwhich is at an oblique angle to the direction of the outside peripheryof said formwork adjacent to said one end face, the other of saidopposite end faces extending from the outside periphery of said formworkto the inside periphery of said formwork in a direction which isnonconvergent to said direction of said one end face, each of saidcomponents of said formwork having inwardly and outwardly facing edgefaces, the length of the outwardly facing edge face of each componentbeing at least as large as the length of the inwardly facing edge faceof the same component, said components being formed on their outsideperipheral surface with a step which faces generally in the samedirection as said outwardly facing edge face, and connecting meanssecuring said components detachably together, said connecting meansincluding a lapping plate carried by one of said components andoverlying another of said components, a pin on said other of saidcomponents engaged in said plate, and a friction latch swingablyparallel to said plate is retaining same in interconnecting relationshipbetween the components.

References Cited UNITED STATES PATENTS 1,075,928 10/1913 Mills 249-39 X2,557,631 6/1951 Callan 249-39 X 2,683,913 7/1954 Honnigford 249--39 XI. SPENCER OVERHOLSER, Primary Examiner.

DE WALDEN W. JONES, Assistant Examiner.

